1. Field of the Invention
The present invention relates to recording apparatus such as copying machines, facsimiles, printers, etc. for recording image data and more particularly to a paper tray control system for use in an apparatus in which various additional devices can be fitted to its base machine.
2. Prior Art
With the spreading use of copying machines in recent years, user requirements tend to become diversified and those which have sophisticated functions have been developed and put on the market in order to deal with the diversified requirements. Relatively new functions being performed by those copying machines include a function of setting a copy contraction/expansion ratio of an original optionally adjustable at the rate of 1% of its dimension, a multicolor copying function using more than two kinds of toner, a monochromatic copying function using one selected color: a continuous copying function on a page-to-page basis by which double-spread two pages of a bookbinding original are copied without moving the original itself; a function of automatically continuously copying both sides of an original or of automatically continuously copying both sides of copied paper; and editing function by which a plurality of originals are edited and copied through synthesizing them or deleting some of them; a job memory function by which copying conditions stored in IC cards are inputted to set the copying conditions automatically; and many other functions.
The trend is for not only copying machines but also other kinds of recording apparatus such as facsimiles and printers for recording image data to be commonly made multifunctional and sophisticated.
Even though the apparatus is set multifunctional, however, all of its functions are rarely employed at all times but some of them are rather partially used, depending on the business or place in which it is installed. Consequently, there has been adapted an arrangement of models ready for supply, ranging from high-class models equipped with all sorts of functions up to special models offering a combination of various functions so that users are allowed to select one of the models capable of meeting their requirements. Moreover, some models are designed so that additional devices are attached in conformity with user requirements to their satisfaction. In any case, a function selective mechanism comprising various switches, buttons or keys is disposed on the console panel in order that any desired functions can be selected from among those provided and started.
An intermediate tray is also one of the additional devices fitted to a copying machine. Once the intermediate tray is added thereto, the paper used to record data can be stocked thereon and reused to record new data. In other words, one sheet of paper can be used to record data several times. A stock mode of the intermediate tray consists of a dual mode in which paper is stocked in such a manner that the preceding recording side is set as a recording side again and a duplex mode in which the back of the preceding recording side is set as a recording side. When the intermediate tray is used in the one or the other mode, the paper used for recording in the body is conveyed up to and stocked on the intermediate tray before being fed to a recording means of the body. Consequently, a conveyer line becomes long and, particularly when a plurality of sheets of paper are continuously designated for recording, the plurality of sheets are involved on the conveyer line extending from the recording means up to the tray. A jam check is therefore imposed on not only the conveyer line of the body but also that of the intermediate tray.
While the aforesaid apparatus is made multifunctional and sophisticated, it ought to become convenient to its user and offer a wide range of application to that extent. On the other hand, it has also posed various problems. In the case of a copying machine equipped with the intermediate tray as an additional device, for instance, copies can be taken in the duplex mode and this makes it necessary to arrange a control circuit for use in taking a one-side copy of a one-side original and a duplex copy of a one-side original. Provided an original autofeeder for use in duplex coping is installed, moreover, a duplex original-duplex copy mode is further added. In the copying machine having the intermediate tray, copy-taking becomes possible in color-making, continuous copying color dualizing, sheet dualizing, parallel dualizing and partial color conversion modes even in the dual mode. As a result, an apparatus adapting a control system capable of exercising control in those modes has to be designed. As the control system varies with the specification of the apparatus, a control device has to be designed to suit each function thereof. Taking a tray for storing recording paper as an example, software for controlling an intermediate tray for duplex recording and editing purposes is provided in a ROM as what is used to control the apparatus proper when the intermediate tray in addition to general trays is installed as an additional device. Accordingly, the memory area of the apparatus proper is ate away as the number of functions added increases.
If attention is turned to part of control on the intermediate tray module (DDM) side, for instance, what becomes necessary on the part of DDM is data of the length and width of paper to be stocked. Accordingly, data on whether the kind of paper for use is of the AB or inch series and what size the paper is has to be specified; the problem is that the number of items of data to be specified increases as the number of paper sizes increases. In case an emergency interrupting situation occurs in the course of conveying paper, it becomes problematical how it has to be dealt with and what kind of control should be exercised therefore. When the main machine is stopped in case of emergency; e.g., jamming or interlock opening, sheets of paper stored in the DDM are set free and displaced as the tray is drawn out. For this reason, jamming and skewing may occur immediately after the operation of the apparatus is restarted.
Procedure and control peculiar to each apparatus becomes necessitated once additional devices are attached and the control system varies as the specification of the apparatus is changed, for example, because of the presence or absence of the additional device. Consequently, its control unit has to be so designed as to suit each combination of additional devices and their functions. Accordingly, the memory area of the apparatus proper is ate away as the number of functions added increases.